package org.shj.hadoop.customeroutputformat;

import java.io.IOException;
import java.util.StringTokenizer;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.shj.hadoop.WordCount;
import org.shj.hadoop.WordCount.IntSumReducer;

public class MultiWordCount {

	public static class TokenizerMapper extends Mapper<Object, Text, Text, IntWritable>{
		private final static IntWritable one = new IntWritable(1);
		private Text word = new Text();
		
		public void map(Object key, Text value, Context context) throws IOException, InterruptedException{
			StringTokenizer itr = new StringTokenizer(value.toString());
			while(itr.hasMoreTokens()){
				word.set(itr.nextToken());
				context.write(word, one);
			}
		}
		
		public static class IntSumReducer extends Reducer<Text, IntWritable, Text, IntWritable> {
			private IntWritable result = new IntWritable();

			public void reduce(Text key, Iterable<IntWritable> values, Context context)
					throws IOException, InterruptedException {
				int sum = 0;
				for (IntWritable val : values) {
					sum += val.get();
				}
				result.set(sum);
				context.write(key, result);
			}
		}

		
	}
	
	public static class AlphabetOutputFormat extends MultipleOutputFormat<Text, IntWritable>{

		@Override
		protected String generateFileNameForKeyValue(Text key, IntWritable value, Configuration conf) {
			char c = key.toString().toLowerCase().charAt(0);
			if(c >= 'a' && c <= 'z'){
				return c + ".txt";
			}
			return "other.txt";
		}
		
	}
	
	public static void main(String[] args) throws Exception {
		String inputPath = "hdfs://192.168.56.101:9000/user/sj/test.txt";
		//输出目录不用预先创建
		String outputPath = "hdfs://192.168.56.101:9000/user/sj/multioutput";
		
		Configuration conf = new Configuration();
		Job job = Job.getInstance(conf, "word count");
		job.setJarByClass(WordCount.class);
		job.setMapperClass(TokenizerMapper.class);
		job.setCombinerClass(IntSumReducer.class);
		job.setReducerClass(IntSumReducer.class);
		job.setOutputKeyClass(Text.class);
		job.setOutputValueClass(IntWritable.class);
		job.setOutputFormatClass(AlphabetOutputFormat.class);
		
		FileInputFormat.addInputPath(job, new Path(inputPath));
		FileOutputFormat.setOutputPath(job, new Path(outputPath));
		System.exit(job.waitForCompletion(true) ? 0 : 1);
	}
}
